Psychologists have identified a great variety of techniques for the control of pain, including behavior modification, relaxation, hypnosis, Lamaze and other "natural" childbirth techniques, and placebos. All such techniques have the effect of controlling the degree to which subjects nonverbally express their pain. Yet recent research has shown that directly controlling the expression of pain leads to substantial pain reduction, as reflected by subjective reports and psychophysiological assessment. Experimental field research is proposed to examine further the effectiveness of nonverbal expressive control on pain in a clinical setting. Subjects will be asked to control overt signs of stress or anxiety while giving blood. Psychophysiological and subjective assessments of stress to the venipuncture will be made to determine the relationship between pain expression and pain experience in a field setting.